The present invention is directed to a connecting terminal of the type having a reversely bent tab stamped therefrom for engaging a wire having an insulating cover whereby upon application of heat and pressure the insulating cover is burned off and the wire is welded to the terminal to electrically connect the wire to the terminal.
In the prior art method shown in FIGS. 1-4, the connecting terminal 1 is obtained by blanking an electrically conductive metal plate such as a copper or copper alloy plate, to obtain a tab 2 which is reversely bent into spaced parallel relation with the plate thereby defining a hook-like portion as best seen in FIGS. 2a and 2b.
An insulated wire 3 connected to an electrical apparatus 5 such as the starter of an electric motor, is connected to the terminal 1 by placing the wire in the bight 2a of the hook-like member 2 with the insulating cover 3a of the wire in firm, intimate contact with the bent portion 2b of the hook-like member as best seen in FIG. 3. With the wire 3 held in this position, the hook-like member 2 is pressed downwardly into engagement with the terminal plate 1 by means of opposed electrode bars 4. A current is then applied to the electrode bars 4 whereupon heat is generated due to the resistance of the terminal plate to burn through the insulating cover 3a and bring the core 3b of the wire into intimate electrical contact with the terminal plate 1 and the reversely bent hook-like member 2 as best seen in FIG. 4. However, in such an operation, foreign material 6 such as unburned parts, oxides or carbides of the insulating cover 3a, may be trapped between the conductive core 3b of the wire and the reversely bent hook-like member 2 as shown in FIG. 4. Since the foreign material 6 acts an electrical insulater or semi-conductor, the foreign material may obstruct a satisfactory electrical connection between the conductive core 3b and the connecting terminal 1. Furthermore, it is difficult to hold the insulated wire in the proper position relative to the reversely bent hook-like member 2 in order to obtain the best possible electrical connection upon application of current and pressure by means of the electrodes 4. Generally, the insulated wire is held by hand which presents a safety problem as well as being disadvantageous from the efficiency point of view.